| From | Paul Gortmaker <> | Subject | [34-longterm 044/247] ALSA: hrtimer: handle delayed timer interrupts | Date | Thu, 23 Jun 2011 13:25:43 -0400 |
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From: Clemens Ladisch <clemens@ladisch.de>
------------------- This is a commit scheduled for the next v2.6.34 longterm release. If you see a problem with using this for longterm, please comment. -------------------
commit b1d4f7f4bdcf9915c41ff8cfc4425c84dabb1fde upstream.
If a timer interrupt was delayed too much, hrtimer_forward_now() will forward the timer expiry more than once. When this happens, the additional number of elapsed ALSA timer ticks must be passed to snd_timer_interrupt() to prevent the ALSA timer from falling behind.
This mostly fixes MIDI slowdown problems on highly-loaded systems with badly behaved interrupt handlers.
Signed-off-by: Clemens Ladisch <clemens@ladisch.de> Reported-and-tested-by: Arthur Marsh <arthur.marsh@internode.on.net> Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> --- sound/core/hrtimer.c | 5 +++-- 1 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/sound/core/hrtimer.c b/sound/core/hrtimer.c index 7730575..07efa29 100644 --- a/sound/core/hrtimer.c +++ b/sound/core/hrtimer.c @@ -45,12 +45,13 @@ static enum hrtimer_restart snd_hrtimer_callback(struct hrtimer *hrt) { struct snd_hrtimer *stime = container_of(hrt, struct snd_hrtimer, hrt); struct snd_timer *t = stime->timer; + unsigned long oruns; if (!atomic_read(&stime->running)) return HRTIMER_NORESTART; - hrtimer_forward_now(hrt, ns_to_ktime(t->sticks * resolution)); - snd_timer_interrupt(stime->timer, t->sticks); + oruns = hrtimer_forward_now(hrt, ns_to_ktime(t->sticks * resolution)); + snd_timer_interrupt(stime->timer, t->sticks * oruns); if (!atomic_read(&stime->running)) return HRTIMER_NORESTART; -- 1.7.4.4
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